The invention relates to an electronic device, in particular a control device, having a housing, which has a cavity, in which there is arranged a circuit carrier fitted with electric and/or electronic components, forming an electric and/or electronic circuit, and having a fuse element making contact with the circuit carrier in order to protect the electric and/or electronic circuit against electrostatic discharges.
Electronic devices comprise electric and/or electronic circuits, which are very sensitive with regard to an electrostatic discharge. An electrostatic discharge can result for a variety of reasons. For example, it is possible that housing parts—for example made from plastic—charge themselves electrostatically. From a certain amount of charge, the electrostatic charge can then jump from the housing onto electrically conductive regions of the electric and/or electronic circuit. It is likewise possible for the electronic device to move into the proximity or in contact with a charge carrying element. It is fundamentally sufficient that a potential difference is present between the electronic device and the further element. In this case, a charge transfer onto the housing of the electronic device can occur, wherein the discharge in turn can move to the electric and/or electronic circuit if a sufficient amount of charge is present. Electrostatic discharges can often damage the electric circuit and/or components of the electric and/or electronic circuit. At the point in time of the electrostatic discharge, operational disruptions of the electronic device can, however, at least occur.
The tolerance with respect to an electrostatic discharge can be checked in electronic devices by special testing methods. In such testing methods, electronic devices, for example control devices, are, for example, subjected to a discharge of air generated by a device in the immediate proximity of the housing wall thereof. In the published German patent application DE 102010040558, such testing methods are, for example, described. A control device comprising a high impedance circuit part on a printed circuit board is likewise known from said published patent application. In order to protect the high impedance circuit part an additional protection element is provided on the printed circuit board, said protection element being connected to ground. In this case, the course of an electric field elicited by an electrostatic discharge outside of the control device is deflected to the protection element. Installation space on the printed circuit board must be put aside for the additional protection element.
In the case of a control device, it is likewise known to design an additional protection element in the form of a spring. Such a spring can then contact an electric and/or electronic circuit on a printed circuit board by means of one end, in particular a ground connection. By means of the other end, the spring contacts on the other hand a housing part of the control device, for example a metallic cover. An electrostatic discharge is always ensured via the spring on account of the direct contact. Such a spring however requires a large area on the printed circuit board layout. Furthermore, the metallic cover must be mechanically fixed to the control device during installation. This is because the spring presses the cover upwards due to the return force thereof. If the cover is, for example, adhesively sealed, the mechanical fixation of the cover must take place until the adhesive has completely cured.
A conductor support is known from the published German patent application DE 102004049053 A1, which has at least one spark route for surge protection between two electric, conductive regions on the conductor support. Such spark routes can be structured on the printed circuit board using conventional etching methods and are suitable for the formation of an electrostatic protection for connecting pins.